Oil-resistant polymer composition

ABSTRACT

AN OIL-RESISTANT POLYMER COMPOSITION COMPRISING (1) 5 TO 50% BY WEIGHT OF A COPOLYMER CONSISTING ESSENTIALLY OF 20 TO 50% BY WEIGHT OF ACRYLONITRILE, 50 TO 80% BY WEIGHT OF A DIENE SELECTED FROM BUTADIENE AND ISOPRENE AND 0.1 TO 10% BY WEIGHT OF AN A,B-ETHYLENICALLY UNSATURATED CARBOXYLIC ACID AND HAVING A NUMBER AVERAGE MOLECULAR WEIGHT OF ABOUT 500 TO 10,000 AND (II) 95 TO 50% BY WEIGHT OF AN ACRYLONITRILE/BUTADIENE COPOLYMER.

United States Patent US. Cl. 260-894 6 Claims ABSTRACT OF THE DISCLOSURE An oil-resistant polymer composition comprising (I) to 50% by weight of a copolymer consisting essentially of to 50% by weight of acrylonitrile, 50 to 80% by weight of a diene selected from butadiene and isoprene and 0.1 to 10% by weight of an a,fl-ethylenically unsaturated carboxylic acid and having a number average mo lecular weight of about 500 to 10,000 and (II) 95 to 50% by weight of an acrylonitrile/butadiene copolymer.

This invention relates to an oil-resistant polymer composition, and more specifically to an oil-resistant polymer composition comprising a copolymer composed essentially of acrylonitrile, butadiene or isoprene and an oc,}3-ethylenically unsaturated carboxylic acid and an acrylonitrile butadiene copolymer.

When rubberis used in a state of contact with chemicals or solvents, changes in the volume, strength and elasticity modulus become important problems, and these phenomena are being investigated as important subjects. Rubber compositions have been selected for practical purposes so that these properties are suitable for the desired end use.

When rubber comes in contact with a solvent, it is frequently broken within a short period of time under a low stretch which would not cause breakage in air. This phenomenon of crack growth in a solvent is known as solvent crack in the field of plastics. However, there have been only a few reports on studies made on this phenomenon in rubber.

The occurrence of solvent crack should naturally be avoided in the case of rubber materials to. be used in contact with gasoline, and therefore rubber compositions based mainly on an acrylonitrile-butadiene copolymer are widely used. As a result of the social demand for excluding a lead ingredient from gasoline, it is expected that the content of an aromatic ingredient (the aromatic content of gasoline now in use is estimated at about 50%) will be increased. The solvent crack phenomenon would therefore becomes a practical problem even with the acrylonitrile-butadiene copolymer compositions. Having assumed such a situation, extensive investigation has been 5 conducted on the solvent crack phenomenon of rubber in a mixed solvent of iso-octane and toluene in a ratio of 40:60. As a result, it has been found that a standard acrylonitrile-butadiene copolymer composition now in wide use has a crack break life, as measured under the conditions to be described, of only less than one minute, and cannot withstand practical use.

It is therefore an object of this invention to provide an oil-resistant polymer composition which undergoes extremely small crack growth when in contact with highly aromatic solvents.

Other objects of this invention will become apparent from the following description.

According to this invention, a composition is provided comprising 5 to 50% by weight of (I) a copolymer consisting essentially of 20 to 50% by weight of acrylonitrile,

50 to by weight of a diene selected from the group consisting of butadiene and isoprene and 0.1 to 10% by weight of an a,/3-ethylenically unsaturated carboxylic acid and having a number average molecular weight of about 500 to 10,000 and (II) to 50% by weight of an acrylonitrile-butadiene copolymer.

When the polymer composition was tested as to it solvent crack phenomenon under the conditions to be described, it was found to have a crack break life of longer than about 5 minutes, thus showing a great improvement. Therefore, the polymer composition of this invention can find utility in a wide range of applications which require resistance to highly aromatic solvents. Since the composition of the invention has far superior resistance to solvent crack when compared with conventional acrylonitrilebutadiene copolymer compositions, it can sufliciently withstand use under severe service conditions such as in gasoline having a high aromatic content.

The low-molecular-weight (about 500 to 10,000) ternary copolymer of acrylonitrile, butadiene or isoprene, and an c p-unsaturated carboxylic acid used in the invention is produced in accordance with a usual emulsion-polymerization recipe. The polymerization temperature may be low (about 0 C.) or high (30 to 80 C.). Therefore, the polymerization initiator may be a Redox catalyst or a free-radical catalyst such as potassium persulfate and organic peroxides. Since the polymerization system isacidic, any emulsifier which has an emulsifying action under acidic conditions may be used. It is preferred that an aqueous emulsifier solution should be acidified prior to the feeding of monomers. Typical examples of a molecular-weight modifier that can be used is a mercaptan such as tertiary dodecyhnercaptan, and its amount is controlled so that a copolymer of the desired low molecular weight can be obtained. Chemicals such as the monomers, molecular-weight modifier and emulsifier may be charged any time before the initiation of reaction, or if desired, in divided portions. The polymerization can be employed either batchwise or continuously. As the a,B-ethylenically unsaturated carboxylic acid, at least one monoor dicarboxylic acid selected, for example, from acrylic acid, methacrylic acid, maleic acid and itaconic acid may be used. The proportion of the carboxylic acid to be polymerized is from 0.1 to 10% by weight. If the proportion is less than 0.1% by weight, the solvent crack resistance of the polymer composition cannot be improved, and if it exceeds 10% by weight, the solvent crack resistance and other properties are undesirably deteriorated.

The polymer composition of this invention is an admixture of (I) 5 to 50 parts by Weight of this low-molecularweight polymer and (II) 95 to 50 parts by weight of an ordinary acrylonitrile-butadiene copolymer having an acrylonitrile content of about 20 to 50% by weight, the sum of (I) and (II) being parts by weight. If the amount of copolymer (I) is less than 5 parts by weight, the solvent crack resistance is not improved, and if it exceeds 50 to parts by weight, the mechanical properties of the composition are lowered. These two polymers (I) and (II) may be mixed in the form of latex or by a mixer such as roll or Banbury mixer or in a solvent.

The coagulation of the latex of polymer (1) and that of polymer (II) can be carried out in a customary manner. The methods generally in practice involve the use of an inorganic metal salt such as chlorides and sulfates of sodium, calcium, magnesium or aluminum or an organic metal salt such as potassium tartrate as a coagulating agent, with or without the conjoint use of an inorganic acid such as sulfuric acid, hydrochloric acid, phosphoric acid or silicic acid or an organic acid such as acrylic acid, citric acid or tartaric acid. The amount of the metal salt is 1 to 5% based on the solids content of the rubber in the latex, and the amount of the acid is to 6% by weight on the same basis. The solvent rack resistance of the composition of this invention can be further improved by using as a coagulation agent an u,fi-ethylenically unsaturated carboxylic acid such as an acrylic acid polymer, a methacrylic acid polymer or an acrylic acid-methacrylic acid copolymer or its ammonium salt and the metal salt in the coagulation of the latex of copolymer (I) or a mixture of the copolymer latex (I) and the copolymer latex (II). Thi coagulation agent is especially preferable since it can inhibit the corrosion of metal machinery in the dehydration and drying process. If desired, this coagulation agent can be used conjointly with the above-mentioned known acid. In this case, the amount of the acid may sufiiciently be as small as up to 2% by weight, and there is substantially no problem of the corrosion of the machinery.

The polymer of an a,fi-ethylenically unsaturated carboxylic acid used to coagulate the copolymer latex is a polymer or copolymer obtained by polymerizing an oat"?- ethylenically unsaturated monoor dicarboxylic acid having 3 to 5 carbon atoms, such as acrylic acid, methacrylic acid, fumaric acid, maleic acid or itaconic acid, in an aqueous medium using potassium persulfate, ammonium persulfate or a Redox catalyst. The acrylic acid polymer, methacrylic acid polymer and acrylic acid/methacrylic acid copolymer are preferred. The ammonium salts of these polymers obtained by neutralizing them with aqueous ammonia or ammonia to a neutrality of 0 to 1 can also be used. Even when the ammonium salt having a neutrality of l is used, a part of the ammonium salt sometimes remains in the form of an acid depending upon its pH at the time of coagulating the latex.

It is to be noted in this connection that these acid polymers and their ammonium salts are usually employed as binders, cosmetics, aqueous paints, adhesives, thickners, etc.

The viscosity average degree of polymerization (p) of these polymers or ammonium salts thereof (as determined by the method described in Herman F. Mark, Encyclopedia of Polymer Science and Technology, vol. 1, page 216, 1964) is usually 50 to 200,000, preferably 500 to 20,000. The amount of the polymer is 0 to 6% by weight, preferably 0.5 to 3% by weight, based on the solids content of the copolymer in the latex. Amounts in excess of 6% by weight sometimes cause a marked rise in the viscosity of the latex, and are undesirable and uneconomical.

The order of adding the coagulating agent to the latex is optional. For example, the acid polymer is first added to the latex, and the metal salt or the metal salt and the acid are added at the time of coagulation. Or all of the coagulating agents may be added separately. However,

acid polymer, especially when the metal is of a divalent nature. To overcome this problem, the acid is used in an increased amount to reduce the pH. If required, a coagulating assistant such as glue and polyamine may be conjointly used. The coagulation is performed at room tem perature or at an elevated temperature according to the usual method. Subsequent water-washing and drying give a rubber composition.

The polymer composition so prepared is vulcanized in a customary manner using sulfur or a peroxide. In addition to the vulcauizing agent, ordinary additives such as a reinforcing agent, extender, softening agent, anti-oxidant or pigment can also be added.

The polymer composition of this invention, like the ordinary acrylonitrile-butadiene copolymer, can be used in a wide variety of fields either alone or in admixture with natural or synthetic rubber in the form of latex or solid, and finds special utility in applications which require good resistance to solvent crack, such as the production of fuel hoses, packings, oil seals, gaskets, belts, rolls for spinning frames, printing rolls or diaphragms.

The invention will now be described specifically by the following non-limitative examples. In each of the examples, all parts and percentages are by weight.

EXAMPLE 1 Polymerization was carried out in accordance with the recipe shown in Table 1 using an autoclave having an inner capacity of about 12 liters at C. until the conversion of the monomer reached 85%. After completion of the reaction, a commercially available anti-oxidant was added to the latex, and the polymer latex was coagulated with an aqueous solution of aluminum sulfate, followed by washing with water and drying in a vacuum dryer to form a liquid copolymer. The combined acrylonitrile content (percent) of the resulting copolymer was measured by the Kjeldahl method. The combined carboxyl group content (moles of COO-H per 100 parts of rubber) was determined by the titration method. The number average molecular weight was measured by an ebulliometer. The properties of the polymer are shown in Table 2.

Potassium persulfate 0.3 Tertiary dodecylmercaptau (varying amounts, see

Table 2).

TABLE 2 Polymerization conditions Properties of the polymer Amounts of monomers charged (parts) Amount of tert.- Combined Combined Number dodeeylacrylocarboxyl average Acrylo- Methaeryllc mercaptan mtrile group molecular mtnle Butadiene acid (parts) (percent) (ephn) weight 10. 0 42. 5 1, 880 45 54. 5 0. 5 10. 0 42. t 0. 005 1, 910 45 53 2. 0 10. 0 43. 1 0. 022 1, 870 45 48. 5 6. 5 10. 0 43. 5 0. 075 2, 020 45 45 10. 0 10. 0 43. 2 0. 110 1, 980 35 63 2. 0 9.0 33. 8 0.024 1, 930 so so 12. 0 45. s 1, sec 50 48 2. 0 12. 0 4.5. 2 0. 021 1, 910 45 53 2. 0 17.0 42.5 0.023 1,150 45 58 2. 0 3. 5 42.8 0. 023 6,010 45 53 l 2. O 10. 0 43. 3 0. 025 1, 980 45 b 53 2. 0 10. 0 43. 2 0. 022 2, 020

I Acrylic acid was used instead of methacrylic acid. b Isoprene was used instead of butadiene.

when the acid is mixed with the metal salt prior to addi- 100 parts of a mixture of the resulting liquid copolymer tion, both react with each other to form a water-insoluble and a commercially available acrylonitrile-butadiene copolymer, 5 parts of zinc oxide, 1 part of stearic acid, 0.3 part of sulfur, 65 parts of FEF carbon black, parts of dioctyl phthalate, and parts of tetramethyl thiuram monosuliide were mixed on a roll and the mixture was vulcanized for minutes at 150 C. The properties and the solvent crack resistance of the resulting vulcanized products are shown in Tables 3 to 5.

The measurement of the solvent crack resistance was made as follows:

Indicator lines were drawn at intervals of 10 mm. on a rectangular test piece 10 mm. wide and 2 mm. thick. Midway between two adjoining indicator lines a crack 2 mm. thick was provided by a razor in a direction parallel to the indicator lines extending to the back thereof. The test piece was mounted to jigs capable of being extended at a stretch ratio of 100%. At this time, the distance between the jigs was adjusted constantly to 30 mm. The test piece was in a taut state in a test solvent (a mixture of iso-octane/ toluene in a volume ratio of 40:60) at 30 C., and the time that elapsed until the break of the sample was measured.

As is seen from the data shown in Table 5, polymer compositions having excellent resistance to solvent crack can be obtained when the molecular weight of the liquid copolymer Was changed (Experiments Nos. 14 and 15), when acrylic acid was used instead of methacrylic acid (Experiment No. 16), and when isoprene was used in stead of butadiene (Experiment No. 17).

TABLE 3 Experiment No.

1 (con- 2 (control) trol) 3 4 5 6 Amount in parts of acrylonitrile butadiene copolymer 100 80 80 80 80 80 Liquid copolymer:

Sample No A B C D E Parts 20 20 20 20 20 Properties of the vulcanized product:

Tensile strength (kg/cm!) 171 139 142 146 158 167 Elongation (percent) 480 530 470 460 480 420 300% modulus (kg./cm.=) 137 106 108 110 114 124 Hardness (J'IS) 67 63 65 64 68 69 Resistance to solvent crack (break tim 0'43" 1'54 4'41" 1204" 1045" 9'23" I Hycar 1041 (product 0! Nippon Zeon 00., Ltd.).

As is seen from Table 3, the acrylonitrile-butadiene co- EXAMPLE 2 polymer alone has poor resistance to solvent crack. The solvent crack resistance of a mixture of the acrylonitrilebutadiene copolymer with a liquid copolymer free from a carboxyl group can be improved only to a slight extent (see Experiment No. 2). By contrast, the polymer compositions of the present invention (Examples Nos. 3 to 6) have extremely good solvent crack resistance.

Polymerization was performed at 5 C. in accordance with the polymerization recipe shown in Table 6 below. When the conversion reached at least 85%, a short stop was added to stop the polymerization reaction, followed by addition of a commercially available antioxidant to form a latex having a combined acrylonitrile content of 42.5% and a Mooney viscosity (100 C. ML of 65.0.

TABLE 4 Experiment N o. 0 12 (con- 7 8 trol) 1o 11 ml) 13 Amount of acrylonitrile-butadlene copolymer (parts) 90 80 80 80 Amount of acrylonltrile-butadlene copolymer (parts) a. 100 80 Liquid copolymer:

ample N n C C C F G H am 10 4o 20 2o 20 20 Properties of the vulcanlz Tensile strength (kg 149 126 166 143 162 142 139 Elongation (percent) 480 520 610 490 460 610 470 300% modulus (kg. 120 94 141 us 109 10s 11s Hardness (-TIS)- 8 63 69 67 63 66 Resistance to solvent crack (break time) 9'13" 17'29" 0'58" 1047" 8'51" 1'39" 12'07" I Hycar 1041. b Hyear 1042 (product of Nippon Zoom Co., Ltd).

TABLE 6 Parts 65 Acrylonitrile 45 As is seen from the results shown in Table 4, polymer gggi g? compositions having excellent resistance to solvent crack Sodium alkylnaphthalenesulfonate': 1.5 can be obtained when the mixing proportlons of the llqlll Sodium alkylbenzenesulfonate 2.0 copolymers were changed (Experiment Nos. 7, 8 and 4), Sodlum y) Phosphate and when the combined acrylonitrile content of the acrylo- Ferrfms sulfate 1H b 1 th b l Tertiary dodecyl mercaptan 0.50 lene copo ymer or e car oxy group-co Sodium ethylenediaminetetraacetate 0,03 ta g llqmd copolymer was changed (Experlments Sodium formaldehyde sulfoxylate 6 10, 11 and 13). i p-Methane hydroperoxide 0.05

A mixture of 80 parts by weight (as rubber solids content) of this latex and 20 parts by Weight (as rubber 8 tables is based on 100 partsby weight of the rubber solids content of the latex. 1

TABLE 8 I Experiment No.

1 (control) 2 3 4 5 Coag'nlating agent:

Metal salt (2.7 parts) Aluminum Aluminum Aluminum Calcium Calcium sulfate sullate sulfate chloride chloride Amount of the acrylic and polymer..... 0. 9 1. B 1. 8 2. 7 Properties of the vulcanization product:

Tensile strength (kg/cm?) 124 117 118 125 130 Elongation (percent) 410 420 440 410 440 300% modulus (kg/cull).-." 10B 94 94 105 103 Hardness (J IS) 66-59 65-57 68-57 67-57 7055 Resistance to solvent crack a Y O slog! 7123!! eloafl fillsll 6I46II 0155i! 2I15II 2'08 2'16 1l'43ll solids content) of latex C obtained in Example 1 was coagulated using a coagulating agent shown in Table 8. A aqueous solution of acrylic acid polymer (Aron A(H) degree of polymerization about 2000 (product of Tea Gosei Kagaku Kogyo Co., Ltd.) was admixed with the latex in advance, and a 0.3% aqueous solution of a metal salt was admixed with such latex at the time of the coagulation treatment, whereby the latex was coagulated at to C. The resulting crumb was washed with water, 'and dried in vacuo at C. for 24 hours to form a rubber. This rubber was compounded on a roll in accordance with the receipe shown in Table 7. The

20 canized rubber composition.

EXAMPLE 3 The procedure of Example 2 was repeated except that 25 the coagulating agent used was changed as shown in Table 9. The solvent crack resistance was measured at 2'0 C. and 40 C. The results obtained are shown in Table 9.

TABLE 9 Experiment No.

1 (control) 2 Calcium chloride (2.7) Calcium chlorid 2.7 coagulating agents (parts) -.{Suliuric acid (0.9) iulfuric acid Properties of the vulcanized products: Bryhc mud polymer (0'9); Tensile strength (kg/cm!) 119 114. Elongation (percent).-. 500 560. %00%dnmod1(1})(kg./cm-') 93 80.

m- 058 68-61- Resistance to solvent crack at- 6357 compounded composition was vulcanized for 10 minutes at 160 C.

The solvent crack resistance of the resulting vulcanized product and its physical properties are shown in Table 8. The amount of the coagulating agent in the following As is seen from Table 9, the use of the acrylic acid polymer as a coagulating agent together with the metal salt and acid gives rise to greater improvement of the solvent crack resistance of the vulcanized rubber composition.

EXAMPLE 4 The mixed latex prepared in Example 2 was coagulated using a coagulating agent shown in Table 10 and washed with water. The resulting rubber crum containing about 40% of water was held between steel plates (SAE-IOZO), and allowed to stand in a gear oven for 20 hours at C. The crumb and the steel plates were taken out, and the corrosion of the surfaces of the steel plates was judged by the naked eye. The results are shown in Table 10.

TABLE 10 Experiment No. v

1 (control) 2 (control) 3 (control) 1 r 4 Co ting ent: V I Y I v a.

etalsalt 2.7 parts) Aluminum sulfate......-...-. Aluminumsultate Aluminum suli'ate.-.'.. Aluminumsuliate. Acid (2.7 nart Sulfuric avid Phosphoric acidu Hydrochloric acid" crylic acid polymer. corrosionofthe p g Considerablylarge Large Small. I

It is seen from Table 10 that the use of an acrylic acid It is seen from Table 12 that the use of an ammonium polymer as one component of the coagulating agent leads salt of the acrylic acid polymer as one component of the to a remarkable improvement in the corrosion of steel by coagulating agent gives rise to a rubber vulcanized prodthe rubber crumb. uct having superior resistance to solvent crack.

EXAMPLE 5 5 In accordance with the polymerization recipe shown in EXAMPLE Table 11, polymerization was performed at 35 C. When the conversion reached at least 85%, a short stop was The PFOcedllre fEXaII}P1e Was repeated except that added to stop the reaction. Then, a commercially avail- Coagulatlng agent shown In Table 13 Was used- The P bl ti id t was dd d t f a latex h i a erties of the resulting vulcanized product were rated. The combined acrylonitrile content of 42.3% and a Mooney resistance to solvent crack was measured at 17 C. and

viscosity (100 C. ML of 57.5. 40 C. The results are shown in Table 13.

TABLE 13 Experimental report 1 (control) 2 Calcium chloride (4) Calcium chloride (2.7). coagulating agent (parts) Sulfuric acid (0.9).. Sulfuric acid (0.9).

Ammonium salt of acrylic acid polymer (0.9). Properties of the vulcamzed product:

Tensile strength (kg/cm?) 113.. 109. Elongation (percent) 490 560. 300% Modulus (kgJcmfi) 98- 94. Hardness (JIS)-.. 68-e1 63-57. Resistance to solvent crack at- TABLE 11 It is seen from Table 13 that the use of an ammonium Parts salt in an acrylic acid polymer together with the metal Acrylonitrile 5 salt and acid gives rise to greater improvement of the Butadiene 55 solvent crack resistance. Water 250 Sodium alkylnaphthalenesulfonate 2.5 EXAMPLE 7 Sodium alkylbenzenesulfonate 1.0 s di Sulf t 0.2 The procedure of Example 4 was repeated using the Potassium persulfate 0.3 mixed latex employed in Example 5, and using the co- Tertiary dodecyl mercaptan 0.52 agulating agents indicated in Table 14.

TABLE 14 Experiment No.

1 (control) 2 (control) 3 C ti t:

il iai ii ff parts) Aluminum sulfate Aluminum sulfate Aluminum sulfate.

Acid or ammonium salt (2.7 parts)--- Sulfuric acid Hydrochloric acid Ammonium salt of the acrylic acid polymer. Extent of corrosion of the steel plate Large Large Small.

A mixture of 80 parts by weight (as rubber solids con- It is seen from Table 14 that the use of an ammonium t nt) of this latex with 20 parts by weight of latex C salt of the acrylic acid polymer as one component of the obtained in Example 1 was coagulated using a coagulatcoagulating agent gives rise to a remarkable improvement ing agent shown in Table 12. in the extent of corrosion of the steel plate by rubber.

A 5% aqueous solution of the ammonium salt of an What is claimed is: acrylic acid P y (Aron A30, degree of P Y 1. An oil-resistant polymer composition consisting estion about 2500, neutrality 1, product of Toa Gosei sentially of (I) 5 to by weight of a ternary copo1y Kagaku Kogyo J was admlxed wlth the above 50 mer consisting essentially of 20 to 50% by weight of mixed latex 1n advance and a 03% aqueous 9 of acrylonitrile, 50 to 80% by weight of a diene selected from the metal salt was added to the latex at the time of cobutadiene and isoprene and (M to 10% by weight of an agulanona treatment whereby the latex was f i at a,,8-ethylenically unsaturated monoor di-carboxylic acid 30 to 40 The resultmg crumb was Washe wlt water selected from acrylic acid, methacrylic acid, maleic acid and dried in vacuo for 24 hours at 50 C. Thereafter the resulting rubber was compounded on a ton in accord: and itaconic ac1d, and having a number average molecular ance with the compounding recipe shown in Table 7 weight of about 500 to 10,000 and (H) 95 to 50% by above, and then press-vulcanized at 160 C. for 10 min- Weight of afilylonitfik/butadiene P Y utes. The properties and the resistance to solvent crack AH oll-reslstant P y composltlon conslstmg of the resulting vulcanized products are shown in sentially of (I) 5 to 50% by weight of a liquid copolymer,

Table 12, said liquid copolymer being prepared by coagulating a TABLE 12 ternary copolymer latex with a number average molecular weight of about 500 to 10,000 consisting essentially of 20 Experiment No. to 50% by weight of acrylonitrile, 50 to 80% by weight 1 (control) 2 3 of a diene selected from butadiene and isoprene and 0.1 ii iiiiiii fiiae Aluminum Aluminum Calcium to 10% by weight of an a,fl-ethylenically unsaturated Amount ammonium Salt of sulfate Sulfate cmmde monoor di-carboxylic acid selected from acrylic acid, t g gg y c a d polymer 0 1.8 1.8 methacrylic acid, maleic acid and itaconic acid, 1n the properges 5f 1551 135555 presence of a metal chloride, sulfate or tartrate and a gggg f strength 134 polymer of an a,B-ethylenically unsaturated carboxyl c l ngation (perce t) 430 500 47 acid selected from poly(acrylic acid), po1y(methacryl1c gfigggg gl gflfifffg? ig: A9? 67329 acid) and an acrylic acid-methacrylic acid copolymer or to ffi ?fi i 1 1 its ammonium salt and t0 Of an 40 C 0' 0" 2' 75 acrylonitrile/butadiene copolymer.

3. The composition of claim 2 wherein said metal salt is aluminum sulfate or calcium chloride, and said ,5- ethylenically unsaturated carboxylic acid polymer is poly- (acrylic acid).

4. An oil-resistant polymer composition consisting essentially of one obtained by mixing 5 to 50% by weight as solids content of (I) a latex of a ternary copolymer of a number average molecular weight of about 500 to 10,000 consisting essentially of to by weight of acrylonitrile, 50 to by weight of a diene selected from butadiene and isoprene and 0.1 to 10% by weight of an e,fl-ethylenically unsaturated monoor di-carboxylic acid with to 50% by weight as solids content and (II) a latex of an acrylonitrile/butadiene copolymer, and coagulating the resulting mixed latex in the presence of a metal chloride, sulfate or tartrate and an a tiethylenically unsaturated carboxylic acid polymer selected from poly(acrylic acid), poly(methacrylic acid) and an acrylic acid-methacrylic acid copolymer or its ammonium salt.

5. The composition of claim 4 wherein said metal salt is aluminum sulfate or calcium chloride, and said a,;3-'

References Cited UNITED STATES PATENTS 6/1945 'Semon et al 260-941 A 11/1962 Frank 260-894 MURRAY TILLMAN, Primary Examiner I. ZIEGLER, Assistant Examiner US. Cl. X.R.

26029.1 R, 29.7 D, PT, 94.7 R

UNITED sTATEsPATENT OFFICE CER'lIF'lCA'IE OF CORRECIIGN Patent NO. 3,790,646 Dated February 5, 1974 Inventor(s) .Tetsu OHISHI ET AL It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as. shown below:

In the Heading, insert the following: Assignors to pp Zeon Tokyo Japan, a corporation of Japan Signed .and sealed this 13th day ofi-A'ugust 197 4.

(SEAL) Attest:

MCCOY M. GIBSON, JR'. 7 o C. MARSHALL DANN Attesting Officer Commissioner of Patents FORM PO-IOSD (10-69) USCOMM-DC 60376- Ff69 U.5. GOVERNMED" PRINTING OFFICE: U, O-OfiQ-JAQ 

